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[2023] Complete day 10
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@connorslade
connorslade committed Dec 10, 2023
1 parent 9783a58 commit e9b50fb
Showing 1 changed file with 148 additions and 31 deletions.
179 changes: 148 additions & 31 deletions aoc_2023/src/day_10.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,8 @@ type Pos = Vec2<usize>;

pub struct Day10;

// This is a mess, but it took me a while to figure out -- so I shall clean it up later (probs like 12 hours)

impl Solution for Day10 {
fn name(&self) -> &'static str {
"Pipe Maze"
Expand Down Expand Up @@ -60,10 +62,82 @@ impl Solution for Day10 {
(len / 2).into()
}

// 501
fn part_b(&self, input: &str) -> Answer {
let maze = parse(input);

let mut pos = maze.start;
let (org_x, org_y) = (maze.segments[0].len(), maze.segments.len());
let mut org_walls = 0;

let mut start = maze.start;
let mut segments = maze
.segments
.iter()
.enumerate()
.map(|(y, line)| {
let mut new = vec![Vec::with_capacity(line.len() * 2); 2];

for (x, c) in line.iter().enumerate() {
if c != &'.' {
org_walls += 1;
}

match c {
'|' => {
new[0].extend_from_slice(&['|', '.']);
new[1].extend_from_slice(&['|', '.']);
}
'-' => {
new[0].extend_from_slice(&['-', '-']);
new[1].extend_from_slice(&['.', '.']);
}
'7' => {
new[0].extend_from_slice(&['7', '.']);
new[1].extend_from_slice(&['|', '.']);
}
'F' => {
new[0].extend_from_slice(&['F', '-']);
new[1].extend_from_slice(&['|', '.']);
}
'L' => {
new[0].extend_from_slice(&['L', '-']);
new[1].extend_from_slice(&['.', '.']);
}
'J' => {
new[0].extend_from_slice(&['J', '.']);
new[1].extend_from_slice(&['.', '.']);
}
'S' => {
start = vector!(x * 2, y * 2);
new[0].extend_from_slice(&[
'S',
match maze.segments[y][x + 1] {
'-' | '7' | 'J' => '-',
_ => '.',
},
]);
new[1].extend_from_slice(&[
match maze.segments[y + 1][x] {
'|' | 'L' | 'J' => '|',
_ => '.',
},
'.',
]);
}
'.' => {
new[0].extend_from_slice(&['.', '.']);
new[1].extend_from_slice(&['.', '.']);
}
_ => unreachable!(),
}
}

new
})
.flatten()
.collect::<Vec<_>>();

let mut pos = dbg!(start);
let mut dir = Direction::Right;
let mut walls = HashSet::new();

Expand All @@ -76,7 +150,7 @@ impl Solution for Day10 {
Direction::Right => vector!(pos.x() + 1, pos.y()),
};

let pipe = maze.segments[pos.y()][pos.x()];
let pipe = segments[pos.y()][pos.x()];
dir = match pipe {
'|' | '-' => dir,
'7' => match dir {
Expand Down Expand Up @@ -104,12 +178,44 @@ impl Solution for Day10 {
};
}

for y in 0..segments.len() {
for x in 0..segments[0].len() {
if !walls.contains(&vector!(x, y)) && segments[y][x] != '.' {
segments[y][x] = '.';

if x % 2 == 0 && y % 2 == 0 {
org_walls -= 1;
}
}
}
}

for line in segments.iter() {
for c in line.iter() {
print!("{}", c);
}
println!();
}
println!();

// Flood fill to find the number of reachable not reachable from the outside
let mut stack = vec![];

// Add perimeter to stack
for x in 0..segments[0].len() {
stack.push(vector!(x, 0));
stack.push(vector!(x, segments.len() - 1));
}

for y in 0..segments.len() {
stack.push(vector!(0, y));
stack.push(vector!(segments[0].len() - 1, y));
}

stack.retain(|x| segments[x.y()][x.x()] == '.');

let pos = vector!(maze.segments[0].len(), maze.segments.len());
// let pos = vector!(0, 0);
let mut stack = vec![pos];
let mut visited = HashSet::new();
let mut outside = 0;

while let Some(pos) = stack.pop() {
let [x, y] = [pos.x() as isize, pos.y() as isize];
Expand All @@ -118,33 +224,44 @@ impl Solution for Day10 {
vector!(x, y + 1),
vector!(x - 1, y),
vector!(x + 1, y),
vector!(x + 1, y + 1),
vector!(x - 1, y + 1),
vector!(x + 1, y - 1),
vector!(x - 1, y - 1),
// vector!(x + 1, y + 1),
// vector!(x - 1, y + 1),
// vector!(x + 1, y - 1),
// vector!(x - 1, y - 1),
] {
if pos.x() < 0 || pos.y() < 0 {
continue;
}

let pos = vector!(pos.x() as usize, pos.y() as usize);

let in_bounds =
pos.x() < maze.segments[0].len() + 2 && pos.y() < maze.segments.len() + 2;
if !walls.contains(&(pos + vector!(1, 1))) && in_bounds && !visited.contains(&pos) {
let in_bounds = pos.x() < segments[0].len() && pos.y() < segments.len();
if in_bounds && !visited.contains(&pos) && segments[pos.y()][pos.x()] == '.' {
stack.push(pos);
visited.insert(pos);

if pos.x() % 2 == 0 && pos.y() % 2 == 0 {
outside += 1;
}
}
}
}
dbg!(
(maze.segments.len() + 2) * (maze.segments[0].len() + 2),
visited.len(),
walls.len()
);

(((maze.segments.len() + 2) * (maze.segments[0].len() + 2)) - visited.len() - walls.len())
.into()

for (y, line) in segments.iter().enumerate() {
for (x, c) in line.iter().enumerate() {
if !visited.contains(&vector!(x, y)) {
print!("{}", c);
} else {
print!(" ");
}
}
println!();
}

dbg!(org_x * org_y, outside, org_walls);
dbg!(org_x * org_y - org_walls);

(org_x * org_y - outside - org_walls).into()
}
}

Expand Down Expand Up @@ -193,16 +310,16 @@ mod test {
"};

const CASE_B: &str = indoc! {"
.F----7F7F7F7F-7....
.|F--7||||||||FJ....
.||.FJ||||||||L7....
FJL7L7LJLJ||LJ.L-7..
L--J.L7...LJS7F-7L7.
....F-J..F7FJ|L7L7L7
....L7.F7||L7|.L7L7|
.....|FJLJ|FJ|F7|.LJ
....FJL-7.||.||||...
....L---J.LJ.LJLJ...
FF7FSF7F7F7F7F7F---7
L|LJ||||||||||||F--J
FL-7LJLJ||||||LJL-77
F--JF--7||LJLJ7F7FJ-
L---JF-JLJ.||-FJLJJ7
|F|F-JF---7F7-L7L|7|
|FFJF7L7F-JF7|JL---7
7-L-JL7||F7|L7F-7F7|
L.L7LFJ|||||FJL7||LJ
L7JLJL-JLJLJL--JLJ.L
"};

#[test]
Expand All @@ -212,6 +329,6 @@ mod test {

#[test]
fn part_b() {
assert_eq!(Day10.part_b(CASE_B), 8.into());
assert_eq!(Day10.part_b(CASE_B), 10.into());
}
}

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